Re: HVM domains crash after upgrade from XEN 4.5.1 to 4.5.2

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 19/11/2015 00:31, Atom2 wrote:
> Am 19.11.15 um 00:17 schrieb Andrew Cooper:
>> On 18/11/2015 22:51, Atom2 wrote:
>>> Am 17.11.15 um 00:10 schrieb Atom2:
> [big snip]
>>> Hi Andrew,
>>> as promised I have again tried with a debug build and the results are
>>> very mixed. I initially tried to better understand what the debug USE
>>> flag actually does in gentoo and my understanding (after reading the
>>> so called ebuilds) is now that the XEN hypervisor will be built by
>>> adding a gcc option of "debug=y" - and that's what should compile a
>>> debug build - right?
>> Yes indeed.
>>
>>> So I went on and again enabled the debug USE flag plus gdb symbols and
>>> rebuilt the hypervisor in the hope that this created a valid and
>>> working debug build.
>>>
>>> It, however, seems there's another problem lurking somewhere which
>>> only manifests itself when I boot from the debug build of the
>>> hypervisor.
>> You did manage to get at least one decent log from a properly
>> debugbuild.
>>
>> However, all we need is the hvm_debug output.  This patch:
>>
>> ---8<---
>> diff --git a/xen/include/asm-x86/hvm/support.h
>> b/xen/include/asm-x86/hvm/support.h
>> index 05ef5c5..7a8fbb5 100644
>> --- a/xen/include/asm-x86/hvm/support.h
>> +++ b/xen/include/asm-x86/hvm/support.h
>> @@ -28,7 +28,7 @@
>>
>>   #define HVM_DELIVER_NO_ERROR_CODE  -1
>>
>> -#ifndef NDEBUG
>> +#if 1
>>   #define DBG_LEVEL_0                 (1 << 0)
>>   #define DBG_LEVEL_1                 (1 << 1)
>>   #define DBG_LEVEL_2                 (1 << 2)
>> ---8<---
>>
>> Will enable hvm_debug in a non-debug build of hypervisor.  Can you try
>> that please?
> Done. Please find the xl dmesg output attached to this mail. I guess
> this time it is really what you were expecting. Whether it does make
> sense though, might be a different issue. But I am confident in your
> abilities to figure out what's going on.

Thanks! That is what I was looking for.

Sadly, it is less useful than I was hoping.  The guest is not appearing
to do anything interesting which causes the bad state; it is almost a
full second between the previous action of note, and the crash.

Can you email me the bad HVMLoader binary please?

~Andrew